diff options
Diffstat (limited to 'arch/x86/include/asm/special_insns.h')
| -rw-r--r-- | arch/x86/include/asm/special_insns.h | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h index ecda17efa042..fde2bd7af19e 100644 --- a/arch/x86/include/asm/special_insns.h +++ b/arch/x86/include/asm/special_insns.h @@ -104,9 +104,36 @@ static inline void wrpkru(u32 pkru) } #endif +/* + * Write back all modified lines in all levels of cache associated with this + * logical processor to main memory, and then invalidate all caches. Depending + * on the micro-architecture, WBINVD (and WBNOINVD below) may or may not affect + * lower level caches associated with another logical processor that shares any + * level of this processor's cache hierarchy. + */ static __always_inline void wbinvd(void) { - asm volatile("wbinvd": : :"memory"); + asm volatile("wbinvd" : : : "memory"); +} + +/* Instruction encoding provided for binutils backwards compatibility. */ +#define ASM_WBNOINVD _ASM_BYTES(0xf3,0x0f,0x09) + +/* + * Write back all modified lines in all levels of cache associated with this + * logical processor to main memory, but do NOT explicitly invalidate caches, + * i.e. leave all/most cache lines in the hierarchy in non-modified state. + */ +static __always_inline void wbnoinvd(void) +{ + /* + * Explicitly encode WBINVD if X86_FEATURE_WBNOINVD is unavailable even + * though WBNOINVD is backwards compatible (it's simply WBINVD with an + * ignored REP prefix), to guarantee that WBNOINVD isn't used if it + * needs to be avoided for any reason. For all supported usage in the + * kernel, WBINVD is functionally a superset of WBNOINVD. + */ + alternative("wbinvd", ASM_WBNOINVD, X86_FEATURE_WBNOINVD); } static inline unsigned long __read_cr4(void) |